Meat quality of broilers fattened deliberately slow by cereal mixtures to higher age. 2. Total lipid, cholesterol and fatty acid content

Three experimental groups (twelve animals each) of female chickens of the R oss 208 hybrid combination were fattened intentionally slow by cereal mixtu res (given from the age of six weeks exclusively). The experimental diets w ere as follows: wheat-type (W) diet fed restrictively (WR), and maize-type diet (M) fed either restrictively (MR) or semi-ad libitum (MS). The fourth group of chickens (control) was fattened a commercial feed mixture ad libit um. Birds were slaughtered when they reached the live weight of 2200 g (46, 74, 87 and 90 days for control, MS, WR and MR group), and were analysed fo r cholesterol by liquid chromatography and fatty acids by gas chromatograph y in breast meat and thigh meat. Slowly growing chickens of all groups deposited more (P < 0.01) cholesterol in breast meat and thigh meat as compared to the control group. MS-chicken s had higher (P < 0.01) cholesterol content in breast meat and thigh meat t han WR-chickens. Total polyunsaturated fatty acids (PUFA) content in thigh meat lipids, and alpha -linolenic acid and linoleic acid concentration in b oth breast meat Lipids and thigh meat lipids of chickens of all slow growin g groups was lower (P < 0.01) as compared to control chickens, despite the higher content of total PUFA in W and M diets in comparison with the contro l diet. Less (P < 0.01) linoleic acid was deposited in thigh meat lipids of WR-chickens than in MR-chickens. Despite the higher linoleic/alpha -linole nic acid ratio in the experimental finishers (W, M), content of eicosapenta enoic acid in thigh meat lipids did not differ (P > 0.05) between all group s of chickens, and content of eicosapentaenoic acid in breast meat lipids o f WR-chickens and docosahexaenoic acid in breast meat lipids of MR-chickens was even higher (P < 0.01) in comparison with the control group. Concentra tion of arachidonic acid decreased (P < 0.01) both in breast meat lipids an d in thigh meat lipids in the sequence: restrictively fed chickens (WR, MR) > semi- nd libitum fed chickens (MS) > fast growing chickens (control). Ar achidonic acid content in breast meat and thigh meat was 67-89 and 113-135 mg/100 g of the fresh matter in experimental chickens (W, M), and 14 and 17 mg/100 g in control chickens, respectively. We conclude that meat of chickens fattened intentionally slow by the cereal diets and slaughtered at twelve weeks contained 20% more cholesterol and s ix times more arachidonic acid, and was therefore less favourable from the viewpoint of a healthy human nutrition than meat of conventionally fed broi lers slaughtered at six weeks of age.